1. Field of the Invention
This invention relates generally to the combustion of fossil fuel and more particularly is directed towards a new and improved method and associated apparatus for improving fossil fuel combustion and the efficiency of fossil fuel combustion equipment.
2. Description of the Prior Art
In designing internal combustion engines, a primary consideration is to achieve combustion conditions such that a maximum amount of the available potential energy in the fuel is converted to mechanical energy rather than thermal energy. From the aspect of thermodynamic considerations it is evident that, even theoretically, only a fraction of this potential energy can be converted to mechanical energy or useful work. In practice, only a smaller fraction can be converted. The ability or inability of the internal combustion engine to achieve the theoretical conversion efficiency is in part due to the combustion process.
When the air-fuel mixture is ignited in the cylinder of a gasoline engine, a flame front spreads out from the point of ignition and ideally this process should continue uninterruptedly until the air-fuel mixture has been completely burned. However, due to the rapid increase of pressure and temperature, which takes place in the air-fuel mixture as the flame front expands, other reactions can take place in the part of the fuel mixture not yet reached by the flame front. Such so-called delay reactions are believed to consist of temperature-pressure induced decomposition of the fuel molecules followed by a nearly instantaneous reaction with oxygen in the mixture. Such a reaction is in the nature of a detonation and results in shock waves that can impart dangerously high stresses on the engine as well as interrupting the orderly spread of the flame front. This phenomenon commonly known as "knocking", reduces the efficiency of the engine and increases the probability of formation of fixed nitrogen (NO.sub.x) as well as unburned hydrocarbons. Even when knocking is not readily apparent such detonations can take place locally in the air-fuel mixture but not to a degree that successively reflected shock waves reinforce each other to the point where the process becomes audible.
To counteract this phenomenon, so-called higher octane fuel is used, the octane rating being the measure of the fuel's ability to undergo compression without audible knocking during subsequent combustion, using as a reference 2,2,4,-trimethylpentane (C.sub.8 H.sub.18) rated at 100 octane. ##STR1##
Anti-knock properties in the fuel are achieved by the use of certain additives, such as tetraethyl-lead, or the use of branched hydrocarbons (alkanes) which, due to the increased compactness of such molecules, are less susceptible to produce pressure-temperature induced detonation. The net effect of the above anti-knock compound is that total air-fuel mixture culminates in a very high percentage burn.
The use of high octane fuel to eliminate knocking presents several drawbacks, including higher cost for such fuel over lower octane fuel and the presence of additives, such as tetraethyl-lead which is not compatible with catalytic convertors now used on most new automobiles to reduce the emission of noxious fumes.
Previous attempts to improve the efficiency of fossil fuel combustion equipment, such as the internal combustion engine, have been only marginally successful. Such measures have included water and steam injection devices, superchargers and the like. None of these, however, has been entirely satisfactory from the standpoint of substantial improvement in combustion efficiency, cost, simplicity, ease of installation and maintenance.
Accordingly, it is an object of the present invention to provide a new and improved method and associated apparatus for improving the efficiency of fossil fuel combustion and the efficiency of fossil fuel combustion equipment, such as internal and external combustion engines, furnaces, boilers and the like. Another object of this invention is to provide a simple, low-cost, efficient method and apparatus for raising the apparent octane rating of gasoline in an internal combustion engine. A still further object of this invention is to provide a novel method and apparatus for generating reactive intermediate compounds for use in fossil fuel combustion equipment.